Facing the challenge of US and Japanese submarines operating within disputed territorial waters, the People's Liberation Army is preparing for a three-dimensional anti-submarine system consisted of aircraft, surface combat vessels and submarines, according to the Hong Kong-based Wen Wei Po.

Meanwhile, the Tokyo-based Yomiuri Shimbun reported that the Japan Maritime Self Defense Force plans to increase the number of its submarines from 16 to 22 by 2021. Using Soryu-class diesel-electric submarines as an example, the paper stated that the size of the new Japanese submarines will become larger. As the first class of Japanese submarines to be equipped with air-independent propulsion system, the Soryu-class diesel-electric submarine can operate under water for nearly two weeks.

The Soryu-class is also much more powerful than its predecessors, the Harushio and Narushio-class submarines, as it is equipped with Type 89 torpedoes and UGM-84 Harpoon anti-ship missiles. Even though Japan is not permitted under its constitution to have its own nuclear-powered submarine, conventional submarines like the Soryu-class are already a dangerous threat to China's maritime communication lines, the paper said, adding that Japanese submarines have a longer patrol range and more powerful weapons systems.

In addition, the United States is deploying more submarines to the Asia-Pacific region. At the US military base in Yokosuka, there are between five and six submarines under the command of the Seventh Fleet. Next year, the US will deploy four more nuclear-powered submarines to Guam, while strategic targets in China are in range of the 154 Tomahawk cruise missiles equipped by a single Ohio-class ballistic missile submarine.